Human-robot collaboration systems (HRC systems) enable the collaboration between humans and manipulators/robots through the use of modern safety technology.
A manipulator of an HRC system is a device, which enables the physical interaction with the environment. In HRC systems, in particular, industrial robots are used, which are automatically guided, multipurpose manipulators equipped with three or more freely programmable axes of motion. Industrial robots are used in either a fixed or mobile manner in industrial applications and bear, for example, end effectors or workpieces. The end effector is the last link of the kinematic chain of the industrial robot and may be, for example, a gripper.
In HRC systems the high output of a manipulator can be combined, for example, with the sensory abilities of humans. Possible applications are, for example, in industrial production, such as in the production of cars. Typical applications are lifting and mounting apparatuses, in which a workpiece is lifted by the manipulator and then positioned by a human. In addition to the resulting potential for rationalization, such applications are advantageous because, for example, the ergonomics of a workplace and/or endurance of a human can be increased.
HRC systems require that the human, collaborating with the manipulator, be not endangered by the manipulator. In particular, the objective is to achieve a machine safety category 3 in accordance with ISO 13849 in HRC systems. In this case an HRC system is considered safe. In order to eliminate a risk to the human, the forces, applied by the manipulator to a workpiece, are often reduced to the extent that no injuries or no serious injuries to a human may occur. In particular, the gripping force of grippers is reduced to such an extent that a human cannot be injured by a grasping of the manipulator. This, however, drastically restricts the range of application. To be able to apply, nevertheless, high forces to a workpiece, extensive safety measures or design measures are necessary.
Design measures to prevent a person or a body part from being, for example, pinched or crushed, often restrict the range of use of a manipulator, because additional safety components are attached, or the working area of the manipulator is restricted. Safety measures comprise, for example, a safe closed-loop position and/or force control of the end effector, thus, increasing the complexity of the calculations. In particular, there is frequent switching between the position and force-controlled mode, as a result of which the control requirements are very high.
The object of the present invention is to eliminate the aforementioned disadvantages at least partially and to provide a corresponding HRC system and a method for controlling an HRC system.